For economical reasons, rapid train lines in the outskirts of areas of high population are often constructed only as single-track lines, with train crossing taking place at intersections. Consequently, any time delay affects trains travelling in both directions. It is therefore very important to carefully adjust the infrastructure, layout of train schedules and distribution of carriages by using e.g. operation simulation programs. For this purpose, a program was developed which is suitable for computer simulation of single track lines in order to evaluate the effectiveness of certain measures and for fast simulation of different possibilities. In order to establish input data and distribution functions to be implemented into the simulation program, data of the computer-aided train-supervision (RZü) Frankfurt/Main were taken and evaluated. Adaptation of the data was necessary, because although the accuracy and integrity of data was sufficient for train-supervision, it was not for simulation purposes. Afterwards, based on a substantial number of data taken from almost 155,000 train movements, travelling times, stopping times, reversing times, delays at departure and frequency of technical faults in dependence of numerous factors as e.g. the traffic-time and load direction were investigated. For developing the simulation program the program-language DELPHI has been used. For the program sequence a procedure was developed, which guarantees a high calculation-speed with a high accuracy of calculation. Before the simulation is started, the unrestrained travelling time was calculated and the time schedule designed by using a travelling time calculation. During the simulation process, the travelling time is only varied stochastically and, in case of train delays, complemented by an additional travelling time which was calculated and stored before the simulation. For simulation of an existing line and for derivation of common recommendations the line from Frankfurt/Main to Darmstadt was selected. It is in some sections a single-track line and allows only a 30-minutes-cycle between Langen and Darmstadt. For a 15-minutes-cycle which is planned in the near future, changes to the infrastructure would be necessary. The question was how these changes would affect the operation quality. Possible measures vary from an additional track in the Darmstadt-Arheilgen station to a complete double-track extension of the whole line. In addition to a separate evaluation of each individual possibility, all possibilities were also compared with one another in order to answer various questions.